328 Fan Temp Sensor Kaput

Nice to have the over ride switch. The other tip, is that every owner should make a simple jumper, from a 6 inch piece of 14 gauge stranded wire, and two male (insulated) spade connectors. With this jumper, you can basically do the same as your over ride switch (just unplug the two spade connectors from the thermoswitch on the radiator and plug in the jumper) and keep the fans running continuously (as long as the ignition is on). Not ideal, but keeps you from impending melt down! I carry one in my car to help out others, and it has come in handy. Once for someone that had a thermoswitch fail, and another time for a guy who had one radiator fan die. By keeping the other fan running continously, he was able to limp it home (but just barely when in traffic).

The other tip, is the thermo switch is the same threading as for most VW applications. Just get the same two pole unit used for a late 70's to early eighties VW Rabbit. About $15. You can even get one in a 10 or so degrees lower setting if you like, though the fans will run a bit more with that.

Dave

 

This is the biggest no-brainer must have for a 3X8 out there. Same EXACT switch. Plus the cooler switch works even better

search for a rabbit jetta scirocco fan switch. 2 pole (VW went to 3 pole in the mid eighties)

 

Guys, is this the switch you are talking about? For $15, I can't think why everyone wouldn't make this change... Any downside/risk in making this modification?
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ZERO

absolutely 100% ZERO

 

In the "stickie" above "Parts Cross References" it list the two VW part numbers.

 

Guys, this is great. I'm doing it.

 

Yes, I think it was Rifledriver (brian crall) that mentioned that a properly running cooling system should not need a cooler thermoswitch. Running the fans more, means more wear and tear on the fan motors...and well, we know those aren't exactly cheap (at least the oem ones). In spite of that warning, I think the downside of that wear is probably minimal.

It IS a solution for marginal cooling systems that might benefit from an overhaul (mainly rodding out the radiator), but just don't have the budget at the moment.

 

He was also one of the few people around here that knew Ferrari's cooling system was inadequate for the QV engine AND said so. I agree.

The youngest cars are now turning 19. That's 19 years of buildup all over inside and out. The fan wear and tear is really a non issue also because when the stock ones do finally crap out only a total moron would buy that same POS fans that came in them to begin with. That is of, course, for a driver. If you have your concours to worry about, buy the original. Otherwise Spal (sp?) work much better.

I put the lower temp aftermarket VW fan switch in my 308 in 1997. That was almost 40,000 miles ago and many many hot Alabama Summer track days ago.

The $15 VW 180 degree is the way to go. Period.

 

Absolutely correct and the original post is regarding a 328 NOT a 308/308QV which, from comments, apparently had a marginal cooling system.

 

The reality is that the difference between a 180 and 195 degree switch is minimal both in wear and tear on the motors and effectiveness at keeping the car cool. On a hot day, the radiator will run hotter than 180 anyway, so the fans are going to come on maybe a minute or two earlier than they would with a 195 degree switch. The question is, when you are cruising on the highway, what temperature does the radiator run at, with all that air being rammed through? If it stays warm enough for the 180 switch to keep the fans on, that could add significantly to their wear and of course your electrical load (which in turn wears the alternator more). With a 195 degree switch, the fans generally will not run on the highway.


Birdman

 

I don't think it is fair to say that these cars have a marginal cooling system. I think it's more accurate to say that they have just barely enough cooling capability, meaning that when everything is working 100%, the cooling system works fine. But there is not much room for error. If anything isn't right (such as radiator gets a little clogged, the thermostat is not opening quite right, the expansion cap is not 100% sealing, both fans aren't coming on, etc.) then the car runs too hot. By comparison, it takes practically a catastrophic failure for a modern car to overheat.

Birdman

 

Marginal=Just barely enough (Jonathan, we're kind of splitting hairs here, don't you think? C'mon on...)

Having owned both a 308QV and a 328GTS, both purchased new...the 308 on a hot day in traffic made me very nervous, as the gauge rose and the overflow cap started to release pressure. On the other hand, nary a problem with the 328 in similar circumstances...

You are so correct though abouut modern cars; we rarely concern ourselves with overheating issues any more..

Regards,
David

 

You're right...I was just thinking that "Marginal" meant "poorly designed" and I don't think that's the case. It's just not designed with much margin for error or extra capacity. They put just enough in there and not a bit more!!

 

You were thinking correctly. Marginal DOES mean it was poorly designed but you know this already from the fuse block issue. There is no car manufacturer that didn't/doesn't realize that crap builds up in coolant systems, that certain markets have a higher ambient temperature than others, that certain sized bearings will only last so long etc. etc. etc.

There is no shame in admiting our cars aren't perfect whether it be a 246, 308, 328, 348 (insert your own model number). For the record, they have defects. They were not designed perfectly.

 

My current switch works fine, but I ordered two switches one for summer one for winter..either way 'just in case'.. think I paid like $6.00 a piece from these guys:

http://www.busdepot.com/

 

I just got the switch myself from Bus Depot, and it's residing in my trunk.

Can anyone post a picture of exactly where it goes, just in case?

 

One of my fans just stopped working and now my car will reach the 195+ mark for the first time. I'd like to try the switch first as changing or fixing the fan motor is a bit more work. Where is the switch located?

 

The switch is in the radiator. Just use a jumper wire across the connector to test the fans without the switch.

 

If i take a 12volt car battery and use two jumpers (one for negative and one for positive side of battery) and clamp them to the prongs of the fan plug is that what you mean by running a jumper wire?

 

No. Simply pull the two wires off the thermo switch. And touch them together. With the ignition on, the fans should start. If they have insulated terminals, then stick a paperclip in between them. If you want to make a "proper" jumper, then cut 3 or 4 inches of 12 gauge wire, and install to male insulated terminals on each end. Then plug that in to the two wires off the thermo switch.

 

Gotcha..thanks.

 

Is the recommended replacement the
Wahler 6010.82D ?

 

Is the original cooling system marginal or are the temperature gauges wrong? No matter what my gauges say, my Motec shows a steady coolant temp. I was speaking to Nick at Forza about this yesterday. The factory gauges just are not very good. If you think you car is running hot, try installing a quality gauge and see if you really have cooling problems.